CONTENTS 



CHAPTER PAGE 



I. INTRODUCTION 13 



SECTION I EFFECTOR SYSTEMS 

 II . SPONGES 25 



III. SPONGES (Continued) 37 



IV. INDEPENDENT EFFECTORS IN HIGHER ANIMALS 50 



V. NEUROID TRANSMISSION IN HIGHER ANIMALS 64 



SECTION II. RECEPTOR-EFFECTOR SYSTEMS 



VI. THE NETJROMUSCULAR STRUCTURE OF SEA- ANEMONES 76 



VII. NERVOUS TRANSMISSION IN SEA- ANEMONES 89 



VIII. JELLYFISHES 102 



IX. THE NERVE-NET 115 



X. TRANSMISSION IN THE NERVE-NET 130 



XI. APPROPRIATION OF FOOD AND THE NERVE-NET 138 



XII. OTHER COMPLEX RESPONSES AND THE NERVE-NET 150 



XIII. HYDROIDS 175 



SECTION III. CENTRAL NERVOUS ORGANS 



XIV. CONCLUSION . 199 



LITERATURE 215 



INDEX . . 225 



9 



